Synthesis and Characterisation of Cosmic Dust Analogue Ensembles from Meteorite Samples 

Abstract

Asteroids have been recognised as the parent bodies of most meteorites (Wylie, 1939), and, as a result of bombardment by micrometeorites and interplanetary dust particles, are believed to be surrounded by clouds of ejected surface dust particles (Szalay & Horányi, 2016).It has recently been postulated by Cohen et al. (2019) that the composition of asteroidal ejecta dust clouds may be determined by the interception of cosmic dust grains by an impact ionisation mass spectrometer aboard a spacecraft conducting a flyby mission (c.f. the Cosmic Dust Analyser aboard Cassini, Srama et al. 2004, or more modern instrumentation, such as the Surface Dust Analyser aboard Europa Clipper, Kempf et al. 2014). The geochemical compositions and abundances of different grains contribute a “fingerprint” identity of an asteroid body, from which the meteorite type most closely linked to the asteroid can be determined.The approach by Cohen et al. (2019) is generally applicable to asteroid flybys at high velocity regimes (approximately greater than 19 km/s), comparable to that of the planned DESTINY+ flyby mission to asteroid 3200 Phaethon. An extension to this technique, applicable to flyby speeds more typical of dedicated missions to the asteroid belt (e.g. 7-10 km/s), was subsequently proposed by Eckart et al. (2023).To test the efficacy of the proposed theories, we intend to generate and analyse ensembles of cosmic dust analogues from meteorite samples, which, following metal coating, will be electrostatically accelerated onto laboratory engineering models, or flight spares, of impact ionisation mass spectrometers, such as the Destiny Dust Analyser, to be aboard the DESTINY+ spacecraft (Krüger et al. 2019). The obtained mass spectral datasets will then be statistically analysed both individually and as a cohort in order to identify unique features, which can lead towards the linking of the mass spectra to the original meteorite type/class.Here we present the latest results and progress in obtaining, characterising, and preparing meteorite samples in order to simulate, within the laboratory, expected data from the impact ionisation mass spectrometry of asteroid dust-clouds aboard flyby spacecraft. The curation of a library of mass spectral data from meteorite mineral phases will largely facilitate the identification of unique meteorite samples and the subsequent tracing of these specimens back to their parent asteroids, providing a deeper insight into the evolution of our solar system. ReferencesEckart, L. M., Hillier, J. K., Postberg, F., Marchi, S., & Sternovsky, Z. (2023). Linking meteorites to their asteroid parent bodies: The capabilities of dust analyzer instruments during asteroid flybys. Meteoritics & Planetary Science, 58(10), 1449–1468.Kempf, S., Altobelli, N., Briois, C., Gru€n, E., Horanyi, M., Postberg, F., Schmidt, J., Srama, R., Sternovsky, Z., and Tobie, G. 2014. SUDA: A Dust Mass Spectrometer for Compositional Surface Mapping for a Mission to Europa International Workshop on Instrumentation for Planetary Missions, p. 7.Krüger, H., Strub, P., Srama, R., Kobayashi, M., Arai, T., Kimura, H., Hirai, T., Moragas-Klostermeyer, G., Altobelli, N., Sterken, V. J., Agarwal, J., Sommer, M., & Grün, E. (2019). Modelling DESTINY+ interplanetary and interstellar dust measurements en route to the active asteroid (3200) Phaethon. Planetary and Space Science, 172, 22–42.Srama, R., Ahrens, T. J., Altobelli, N., Auer, S., Bradley, J. G., Burton, M., Dikarev, V. V., et al. 2004. The Cassini Cosmic Dust Analyzer. In The Cassini-Huygens Mission: Orbiter In Situ Investigations, edited by C. T. Russell, 2nd ed., 465–518. Dordrecht: Springer.Szalay, J. R., and Horányi, M. 2016. The Impact Ejecta Environment of near Earth Asteroids. The Astrophysical Journal 830: L29.Wylie, C. C. 1939. Where Do Meteorites Come from? Science 90: 264–65.